Thanks to everyone for their help.

I finally managed to clean install Win 10 from USB and thankfully only had to format 1 partition of my SSD so no data loss. In fact, cleaned up the boot...

Quick question though - my windows was on a SSD drive separate from my D: drive where all files were kept - will clean install to SSD lose the files on D?

My copy of Win 10 was registered as far...

Right... have tried to boot from USB but startup Repair is unable to fix.
Reset PC doesn't work.
It has an option for UEFI Firmware settings - not a clue what that is.

:(

Had win 7 for years and no idea of product key - came ready installed from YoYotech... probably had the paperwork somewhere but goodness knows where! Will check the comp for stickers however it's...

Aha..

bootrec /fixmbr
bootrec.exe /fixboot
bootrec.exe /RebuildBcd

Managed to restore old version of windows (Windows 7) so am hoping this is going to solve things for me. Will then...

Cheers for the reply.

Am going to try the USB boot method (creating at moment). I can get into all the options to boot in safe mode, recover etc but nothing works. Cannot revert...can't do...

Argh! Need help!

Windows 10 installed and have an Nvidia grfx card which caused a problem with the driver which I managed to get round. Been using Windows 10 quite happily, until today.

PC...